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Menachem, I think we need to differentiate between what PMDs we specify and what
other PMDs we enable. For instance, I don't think it is the IEEE's place to
specify an ULH PMD in terms of the optical specifications. However, this could
be one of the more important applications of a HS Ethernet. So I think it would
be worthwhile for us to enable vendors to develop it in a straightforward
fashion. Thus I think we should get into some of the details that you mention including: 1. PHY
layer – what degree of compatibility with LAN-PHY, WAN-PHY (SONET/SDH),
and/or G.709 is desired? 2. What
amount of differential delay (skew) will be allowed? What will be mandated for
all conformant implementation? It is clearly desirable to maintain compatibility with today’s DWDM
transponders. This is a specific goal of some carriers that are participating
in this process. Carriers would love to have a PMD option that leverages the 10G
LAN-PHY or WAN-PHY. Of course this will depend on the answers to these
questions and other decisions we make. Many (I believe most) DWDM systems on the market now support the
LAN-PHY natively by simply speeding up the G.709 OUT to run at ~11Gb/s instead
of 10.7Gb/s rather than by doing some sort of overhead compression into
SONET/SDH or the G.709 digital wrapper. Drew _____________________________ Drew Perkins Chief Technology Officer Infinera Corporation Phone: 408-572-5308 Cell: 408-666-1686 Fax: 408-904-4644 Email: dperkins@xxxxxxxxxxxx WWW : http://www.infinera.com _____________________________ -----Original Message----- Geoff, Thanks for your comments. I also believe that our efforts should focus on distances no higher
than 10's of Km (up to and including metro). If we decide as a group that it is an objective to make it easy to hook
into LH and ULH transport systems in the installed base, we will have to study
a number of issues such as: (A) should we pick a data rate that is matching SONET rates? (B) should we design our 802.3 std so that it tolerates a much larger
inter-lane differential delay than what would be expected in a metro
application of the standard? (C) should we assume we never go through existing LH transponders and
just have to COEXIST on the same fiber, optical amplifiers, dispersion
compensators located in the huts, optical mux demux at both ends etc. Etc. In this case we would assume a new type of LH tranponder purpose
built for HSSG applications. If this is the case, SONET rate compatibility would not be important. Today's 10G LH and ULH system run mostly at OC-192 rates plus FEC
overhead. Chip vendors were creative and managed to find ways to build devices
that pack into these solutions the full 10G LAN data rate even though OC-192 is
less than 10G. I think (but I may be wrong) that they use available bandwidth in the
management bits available in Digital Wrapper or something like that. Not clean but seems to work... Cheers, Menachem Menachem Abraham -----Original Message----- From: "Geoff Thompson" <gthompso@xxxxxxxxxx> Date: Tue, 22 Aug 2006 16:09:11 To:mabraham@xxxxxxxxxxxxxxxxxxxx Cc:STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx Subject: Re: [HSSG] Reach Objectives Menachem- Thanks for your much more specific answer to the question. I'm afraid
that my earlier answer was handicapped by my ignorance of the specifics of that
market. Based on what you said, I believe the questions for us to consider or
not are: a) Will we consider long haul solutions. OR b) Will we limit ourselves to metro solutions and "transport
end" (i.e. stuff that hooks into the transport infrastructure) solutions. Back in the old days of 10Gig we spent an awful lot of time discussing
the need for the WAN PHY to address case "b)". I think most of us
didn't get it then. I would hope that with a different cast of characters
involved in the discussions that we (or at least I, for one) could come out
with a clear rationale for what we choose. (Just FYI, I believe the crux of the issue came down to whether or not
one could have a 2 port bridge, as opposed to an Optical-Electrical-Optical
repeater in a Transport Chassis.) None the less, I believe that my proposed answer stands. We don't need
to tackle this issue in the first set of objectives and projects. I do remain interested (old repeater hack that I am) in looking into
an O-E-O repeater that does not necessarily come all the way back up to the
level of reassembling the full packet. Geoff At 01:30 PM 8/22/2006 , Menachem Abraham wrote: All, If we decide to include in our reach objectives Long Haul (e.g. 1000
km with optical amps placed at 80 Km spacing) and Ultra Long Haul (e.g. 3000
Km with optical amps at 80 Km spacing, without Optical-Electrical-Optical regeneration), we need to keep in mind that modulation/encoding/FEC
choices play an important role in how far we can go on an optical amplifier
based line system. Such PMD designs may be too costly for our < 80Km applications/objectives so we may end up with more PMDs. While there are some examples of Routers / Switches which have LH or
ULH optical interfaces built in, most systems use Routers / Switches with shorter reach interfaces connected to separate Transport Chassis that
house proprietary LH or ULH solutions. As far as I know the LH and ULH world
does not have interoperable standard solutions today in terms of the
signaling on the fiber. My input for our activities in HSSG is to optimize for cost and not
require that one of our PMDs be directly useable as part of a LH or ULH line
system (unless that is doable without incremental cost). Having said that, I believe we should debate the need to address
"ease of HSSG data transport" on top of existing and emerging LH and ULH
transport systems. If this debate already happened as part of the 10G 802.3
standard development and the conclusions apply here, perhaps somebody can
educate those of us who were not involved at that time. Thanks, Menachem -----Original Message----- From: Aaron Dudek [mailto:adudek@xxxxxxxxxx:
<mailto:adudek@xxxxxxxxxx> ] Sent: Tuesday, August 22, 2006 12:50 PM To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx Subject: Re: [HSSG] Reach Objectives Geoff, Shouldn't the migration to ULH systems have any impact on the spacing and hence be taken into consideration? Or is that beyond the scope for
now? Aaron Dudek (703) 689-6879 Sprintlink Engineering adudek@xxxxxxxxxx On Tue, 22 Aug 2006, Geoff Thompson wrote: > Roger- > > At 03:47 AM 8/22/2006 , Roger Merel wrote: > > Agree with Drew. Have a
few additional comments on other reachs: > > For reach objectives, we
should start with customer based needs (for broad market potential) and only amend if an > obvious technical limitation
with compelling economics can t readily meet the broad customer need. > > Specifically: > > - Long Reach probably should
be set at 80km rather than 100km (as this is the common hut-to-hut amplifier spacing > in telecom) > > - While 50m does serve a
useful portion of the market (smaller datacenters and/or the size of a large computer > cluster), it is somewhat
constraining as I ve been lead to understand that the reach needed in larger datacenters > is continuing to out-grow the
100m meter definition but the 100m definition at least serves the customer well. > Certainly 10G-BaseT worked
awfully hard to get to 100m (for Datacenter interconnect). > > > I wouldn't attach a lot of creedence to the 10GBASE-T goal for
100 meters. It was, I believe, mainly driven by the > traditional distance in horizontal (i.e. wiring closet to
desktop) distances rather than any thorough examination of data > center requirements. > > Geoff > > > - For both in-building
reaches (50m & 300m; or 100m & 300m), the bigger issue which affects the PMD is the loss > budget arising from the
number of patch panels. The shorter / datacenter reach should include a budget for 1 > patch panel. The longer
/ enterprise reach should include a budget for 2 patch panels (one in the datacenter and > 1 in the remote switch
closet). > > > > > From: Drew Perkins
[mailto:dperkins@xxxxxxxxxxxx: <mailto:dperkins@xxxxxxxxxxxx> ] > Sent: Tuesday, August 22,
2006 1:24 AM > To:
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx > Subject: Re: [HSSG] Reach
Objectives > > > > John, > > > > I suggest dividing Metro into
Metro Short Reach at 10 km (equivalent application to 10GBASE-LR) and Metro > Intermediate Reach at 40 km
(equivalent application to 10GBASE-ER). > > > > Drew > > _____________________________ > > > > Drew Perkins > > Chief Technology Officer > > Infinera Corporation > > > > > > > > Phone: 408-572-5308 > >
Cell: 408-666-1686 > >
Fax: 408-904-4644 > > Email:
dperkins@xxxxxxxxxxxx > > WWW :
http://www.infinera.com: <http://www.infinera.com/> > > > > > > _____________________________ > > > > ____________________________________________________________________________ ________________________________________________________ > From: John DAmbrosia
[mailto:jdambrosia@xxxxxxxxxxxxxxxxxxx:
<mailto:jdambrosia@xxxxxxxxxxxxxxxxxxx> ] > Sent: Monday, August 21, 2006
9:38 PM > To:
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx > Subject: [HSSG] Reach
Objectives > > > > All, > > We have had some conversation
on the reflector regarding reach objectives. Summarizing what has been discussed > on the reflector I see the
following > > > > Reach Objectives > > Long-Haul -->
100+ km > >
Metro --> 10+ km > > > > > > > > Intra-rack > > Inter-rack > > Horizontal runs > > Vertical risers > > > > Use this data to identify a
single low-cost solution that would address a couple of the reach objectives > > > > Other Areas > > During the course of the CFI
there were individuals who wanted Backplane Applications kept in for consideration, > but I have not heard any
further input in this area. Are there still individuals who wish to propose Backplane > as an objective? > > > > John > > > > > |